TIGHE NEIRA, RICARDO MARCELO
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Phytochemical characterization and antioxidant properties of Prumnopitys andina fruits in different ripening stages in southern Chile
The native conifer lleuque (Prumnopitys andina (Poepp. ex Endl.) de Laub.) grows in southern Chile, and has an edible and fleshy ovoid fruit. Some species of the genus Prumnopitys are valuable for the medicinal value of their edible fruits. Thus, the aim of this research was to characterize the phytochemical and antioxidant compounds in four ripening stages of P. andina fruits from La Araucanía Region, Chile. Fruit quality related parameters, bromatological, antioxidant and phenolic compounds analyses were performed in order to highlight their potential for human consumption. Our study showed that fresh weight, equatorial diameter, and soluble solid content significantly increased (P < 0.05) in P. andina fruits during ripening, reaching 4.02 ± 0.2 g, 17.9 ± 0.6 mm, and 23.7 ± 0.5 °Brix, respectively, per fruit at stage IV. Our bromatological analyses showed that P. andina fruits had 1.17 ± 0.1 g 100 g-1 DW protein, 1.55 ± 0.2 g 100 g-1 DW crude fiber, and 10.76 ± 2.2 g 100 g-1 DW fruit of ash at fruit ripe. Likewise, we found 2.6 ± 0.2 mg g-1 FW total phenols, 2.2 ± 0.2 mg trolox equivalent g-1 FW of antioxidant activity, and 6.4 ± 0.2 mg rutin equivalent g-1 FW total flavonoid in P. andina fruits. Interestingly, ripening stages I and II showed higher antioxidant compound levels compared to stages III and IV, with the exception of total anthocyanins, which did not change throughout the ripening process. This study shows that P. andina has great potential as a fruit with significant functional properties, which could help promote the propagation, care, and use of this native conifer. © 2022 Elsevier B.V., All rights reserved.
Physiological and molecular effects of TiO2 nanoparticle application on UV-A radiation stress responses in Solanum lycopersicum L.
Nanoparticles (NPs) of titanium dioxide (TiO2) alter photosynthetic and biochemical parameters in Solanum lycopersicum L., possibly due to their photocatalytic properties given by energy absorption in the UV-A range; however, the joint effects TiO2 NPs and UV-A radiation are not well understood. This work evaluates the combined responses of TiO2 NPs and UV-A radiation at the physiological and molecular levels in S. lycopersicum. In a split growth chamber, the presence (UV-A +) and absence (UV-A ?) of UV-A were combined with 0 (water as a control), and 1000 and 2000 mg L?1 of TiO2 NPs applied at sowing. At the end of exposure (day 30 after sowing), the photosynthetic performance was determined, and biochemical and molecular parameters were evaluated in leaf tissues. Better photochemical performance in UV-A + than UV-A ? in control plants was observed, but these effects decreased in 1000 and 2000 mg TiO2 L?1, similar to net CO2 assimilation. A clear increase in photosynthetic pigment levels was recorded under UV-A + compared to UV-A ? that was positively correlated with photosynthetic parameters. A concomitant increase in total phenols was observed on adding TiO2 in UV-A ? conditions, while a decreasing trend in lipid peroxidation was observed for the same treatments. There was an increase in psbB gene expression under TiO2/UV-A + treatments, and a reduced expression of rbcS and rbcL under UV-A ?. These results suggest that the reduction in photosynthetic performance on applying high doses of TiO2 NPs is probably due to biochemical limitation, while UV-A achieves the same result via the photochemical component. © 2023 Elsevier B.V., All rights reserved.